In the traffic environment one aspect that occupies several disciplines is the aspect of traffic safety. All disciplines have to think about that different traffic safety measures have other effects than just reducing the risk of being killed or injured, such as increased travel time, inconvenience, environmental impact, etc. The dividing line between economist and other researchers is that economists study to what limit it is possible for the individual to give up money and wealth in order to improve traffic safety, like the relation between the increase in utility from the safety improvement and the increase in costs induced by the undertaken measure. One recent event that divided traffic safety researchers into two groups was when the Swedish parliament in 1997 decided that the Vision Zero should be the underlying principle of the Swedish traffic safety policy. While most researchers liked the decision, economist strongly disagreed to it. The point of the Vision Zero is zero dead and severe causalities in the traffic environment, and is meant to be a guide for traffic policy makers. One of five principles to justify the Swedish Vision Zero states that "One must always do everything in one's power to prevent death or serious injury. The reason why several economists disagreed to this vision is that it states that human lives cannot be exchanged for some gain. For example, it rules out the trading of lives for other commodities. So, decision-making in line with the Vision Zero can never be regarded too expensive to save lives. Since this is an opinion shared by many policy-makers and the public, it is important for economists to show why the trade-off exists and why it is important to take it into consideration. If the public and policy-makers can learn to understand why the trade-off exists, then it will be much easier to get acceptance for risk values.
Since traffic safety, for example from investing in new roads, is a non-tra